I'm renovating nine 1960's and six early-1970's transceivers, so info will appear here as work
progresses. I have good documentation for each and there is a lot of circuit
information available on the Internet. Here is a hastily-taken too-dark
photo of part of the collection :-

It is great fun bringing an old transceiver back to life or improving its
performance. Many of these radios have lain unused for years which often results
in more than one fault simultaneously, so lateral thinking is needed when
fault-finding. A common fault in
old transceivers is that many resistors change value - they almost always go high in
value - for example in the NCX-3 a 33kohm screen-supply
resistor had changed with age to become 54kohm - the
difficult part is deciding what is an acceptable 'range' of values for that
resistor which will not degrade the performance of that part of the circuit. As a first step I am repairing the major faults and getting each
transceiver to work fully on 1 band, then later I will realign/repair so that
all bands are working well.

Purchased for £200 in 1998, complete with 516F-2 AC PSU and
matching 312B-5 external VFO and Control Unit. This radio works, but there are some problems with
trimmer capacitors sticking (a standard fault), so it needs these replaced
before it can be properly aligned. It came with dozens of spare valves (e.g.
13 x 6146 PA valves), a spare 70K-2 VFO assembly and a retro silver Turner desk
mic. - excellent.

Unfortunately the transformer in the
516F-2 PSU gives secondary voltages which are too high when fed with 230v AC, so
I'm having to use an auto-transformer to run the unit on about 200v AC.
I've replaced the 'upgrade' solid-state rectifiers with the original valve
rectifiers which has helped to reduce the HT voltages to their correct values. Uses a high-impedance
microphone and an external loudspeaker, which is contained in the 516F-2 (there
is also another loudspeaker in the 312B-5). There is a rare DX-Engineering VOX
unit fitted internally.

The most difficult job so far has been repairing the 70K-2 assembly in the
312B-5 external VFO - these VFOs are permeability tuned - the ferrite slug
which moves is on a threaded metal shaft and there is a glass (i.e. insulating) ball-bearing at
the end of the thread. This VFO dial was only covering about 110kHz of its
200kHz range (again this is a common fault) - the grease used to lubricate the
thread dries out and jams the moving ferrite. This repair was fiddly and I had
to be very careful reassembling the unit, but it now works well. The Collins
dial mechanism is also complicated and needs some 'trial and error' to align
the mechanical end-stops with the 'HRO' style dial mechanism and the VFO shaft.

Collins design was remarkably forward-thinking - this radio (approx 1968
vintage) has provision for amplifier switching, split operation, etc. The 312B-5
external control unit has a built-in RF Wattmeter (0-200W and 0-2000W) for use
with the transceiver or companion 30L-1 or 30S-1 amplifiers.

This particular KWM-2A has a 'Pacifica Products' badge on the front panel
(just visible below the main tuning dial)- a still-trading Hong Kong based company that purchased ex-Vietnam War radio equipment and sold it
on to the amateur and commercial markets. Pacifica Products was run by the
larger-than-life figure (500lbs = 33stones = 227kg) of Phil F.Wight W5UHK/VS6DR, who died in June 1997
at the age of 57- it's an
interesting story that I will relate at length here in due course. It is possible, therefore, that this radio
is Vietnam War surplus - all I know for sure was that it was in that part of the
world at some stage of its history.

Purchased for NZ $200 (£74) in November 2004. This radio works, but still
needs a lot of work to make it 100%. The biggest problem is the home-made power
supply, which was lethal ! When first switched on, even using a Variac to slowly
increase the AC input voltage, a choke nearly melted and one electrolytic
capacitor nearly blew up. I've modified and improved it, but the transformer
used is unsuitable for producing the +575V DC needed for the 12DQ6B sweep tubes
in the P.A.

This radio is well made - the valve VFO is very stable, and by using
xtal mixing this stability is transferred to the higher bands. The VFO design is
far superior to the KW2000A or KW2000B (simultaneous FM/SSB transceiver!). Construction is
solid. VOX (which I hate and never use) is standard, but there is no CW sidetone.
Uses a high-impedance microphone, but needs an external loudspeaker. The (I.F. =
1650kHz) crystal filter is 2.7kHz wide, which is too wide for the crowded bands
of 2006, but the shape-factor is quite good.

Renovations of this radio are progressing well - it does however use some
unusual tubes/valves which are proving difficult to replace e.g. 6T8A ( = EABC80
= 3 diodes
in the one envelope) The SR-150 transmitter suffers from a
design/manufacturing fault - a missing bypass capacitor on the anode of a
cathode follower means it acts as an audio amp instead and contributes ALC
voltage on SSB peaks - reducing the peak output to about 50W - this is the mod
required to fix this - quoting Don Power K0TNP "On
my rig (the only one I have had experience with) the problem turned out to be
un-bypassed B+ bus. No bypass shown on the diagram. So maybe at a later date
they corrected the problem.Referring to the
schematic - the triode section of V-3B is a cathode follower in the balanced
modulator. If you follow the plate supply back to its source, there is no audio
bypass. This makes V-3B an audio amplifier. And following this audio output, it
goes through R-113, supply for the aalc amp. V-5B. and then C-154 and voltage
doubler CR-7 and CR-8 and appears as aalc voltage. Reducing the gain of the
driver stages. A 1 or 2 mF cap will bypass the plate
of V-3B and make it a cathode follower as it was meant. This will allow the aalc
circuit to operate normally. The output on voice will be up where it should
be" - thanks Don. This
radio is now waiting for its PSU to be rebuilt.

Purchased for NZ $350 (£140) in September 2005, complete with RV-4C external
VFO which includes a loudspeaker and a home-made copy of the AC-4 power supply. The plug-in noise blanker is
not fitted. This radio is slightly unusual in
that it is 'long and narrow', with controls on the front, rear and sides, and
connectors on the side, rear and underneath. The Drake TR-4C is regarded by some
as the last and best of the valve SSB transceivers. Late model TR-4Cs were
briefly marketed in parallel with its successor the solid-state TR-7
transceiver. See http://www.zerobeat.net/drakelist/drakemod/drmod90.html
for more info.

This radio is in reasonable condition, but some of the aluminium cans show slight corrosion. Some of the
valves used in the TR-4C are a bit rare. The receiver had a fault - the 'RF Gain'
control did not work and there seemed to be no AGC action. This turned out to be
a faulty valve - V12 (12BA6) had grid to cathode leakage which was pulling the
AGC line down. I've also had to strip down and repair the 'S' meter which stuck
at full scale. The permeability-tuned transistorised VFO seems good.

The microphone connector on the TR-4C (and on the Collins KWM-2A) is a stereo
connector which looks like a standard 0.25" one, but is 0.2" diameter.
Luckily I have 5 spare plugs for the Collins so I have used one of these.
I've tested the TX on CW and on SSB - it delivers nearly 150W of RF on 80m,
which is fine. I
wasted about an hour chasing a 'no output on SSB' problem, before discovering a
TR-4C quirk - there is no RF output on SSB if the CW key is plugged in !

February 2006 - another fault developed - the coil of the main changeover
relay (K1) went open circuit. This relay has 6 sets of c/o contacts and a 15000
ohm coil, for 110V DC approx. Rather than mail-ordering a replacement relay, I
changed the faulty coil for a 7000 ohm coil from a similar 100V relay I had -
this involved some very tricky soldering of thin wires, but the end result is
good - the TR-4C is back to full working order. I've added a reverse-biased
1N4007 diode across the relay coil to help reduce the chance of a similar
failure.

Purchased for NZ $30 (£11) in April 2005 - in reasonable condition and complete with the original Swan 230-X AC power
supply. This transceiver has now been repaired and is working on receive but not
very well on transmit - only 100W RF output. Studying the circuit diagram, it becomes obvious that the Swan design is
'cheap and cheerful' - covers 80-10m - using a 5.5MHz xtal filter and
band-switched VFO which inevitably will drift, especially on the higher bands.
On the top of the VFO compartment are plastic plugs which allow access to trimmer caps for VFO
calibration - one for each band 80-10m. Quote from the manual "drift from a
cold start will be less than 1kc for the first hour on 80,40,20m and less than
2kc on 10 and 15m" Surprisingly, drift is not too bad in practice -
at least on 14MHz-
this is an early 2N706 transistor VFO.

There is some surface rust on the PA box, but otherwise the chassis is
fine. The PA tubes should be 6LQ6 (6JE5) but have been replaced by type
6B-B14 - an unusual Japanese type (probably identical to the 6LQ6) which I am
having trouble finding info. about so far. Uses a high-impedance
microphone - has internal loudspeaker fitted. The (I.F. = 5.5MHz) crystal filter
is 2.7kHz wide, which is too wide for the crowded bands of 2005 and the
shape-factor is not very good (4.6kHz at -60dB)

The construction reminds me of
a Heathkit - in fact the manual contains 'Heathkit-like' wiring diagrams for
owners to make various additions or modifications ! The 230-X power supply is
laughably small for a transceiver which claims power input of 500+ Watts, there
are no cooling holes in the PSU metal covers and no fan on the transmitter PA
unit. The electrolytic capacitors in the PSU are strange cardboard-covered ones.

The initial fault in the receiver was that C202 was U/S - this is a
chassis-mounted can electrolytic capacitor (3 x 30uF 450VW), providing
additional smoothing and decoupling - once C202 was replaced (which involved
enlarging the mounting hole in the steel chassis which was difficult to cut -
using a 1.125" Q-Max cutter) the self-oscillation on receive was cured.
After about an hour of testing, a reverse-biased diode started to 'leak' which
resulted in the AGC line voltage rising slowly to about -6V, cutting the
receiver gain drastically. Replacing the diode cured this second fault and the
receiver seems sensitive. It's strange having to peak a signal on receive using
the PA grid, tune and load controls ! RF power output is only 100W maximum so
far. For some inexplicable reason I like this
odd-ball radio !

Purchased for NZ $30 (£11) in May 2005, complete with 2 power supplies (one
with a label clearly stating - transformer burnt out). This radio worked first
time on receive, but does not transmit yet. It's a bit tatty, but you don't
expect much for $30. Uses a 9MHz I.F. filter with claimed selectivity of 2.3kHz
at -6dB and 4.0kHz at -60dB - note the narrowing of the 'standard' SSB filter
bandwidth from 2.7kHz to 2.3kHz as we move into the 1970s. The 7360 beam-deflection tube used as the balanced
modulator in this transceiver is renowned for going 'microphonic'. In its day,
the FT-200 was actually quite a good radio, despite the low price.

Below is a photo of the underside of the burnt-out original Yaesu FP200 PSU - the case and HV
electrolytics have been cleaned up and will be used for the new PSU for the Hallicrafters SR-150.
Lucky that this frying transformer did not burn down the previous owner's smoke-filled
shack !

Horrible isn't it ...the tar has melted right out of the transformer,
vapourised and
coated everything. It was so hot that it desoldered one of the large
disc-ceramics you can see on the xfmr. The PSU which replaced it is well-constructed
-
at first glance it is
difficult to tell if this PSU is home-made or a modified commercial product,
apart from the 'toilet-roll' insulation on one capacitor (presumably to stop it
shorting to the retrofitted smoothing choke). The
wiring underneath has all the hallmarks of a commercial unit, but there are too
many self-tapping screws - so I think it is a commercial product that has been
modified.

I've only played with this radio for an hour - it works well on receive.
I only owned an FT-200 briefly, but it was a noticeable step forward from my KW
Electronics KW2000, Frontier Electronics FE-600 (worst transceiver ever!) and my
somewhat flaky Yaesu
FT-dx-560, but that's another story...

Purchased for NZ $120 (£48) in June 2005, complete with FP200 power supply
(with built-in loudspeaker) and hand microphone. In much better
condition cosmetically than the black FT-200 above, but electrically maybe not
in such good condition ? This radio has had some modifications - the PA valves have
been replaced by 6146s and the RX RF amp and 2nd IF amp (both 6BZ6) have been
replaced by EF183s. The PA mod is a standard sensible mod given the difficulty
in obtaining 6JS6Cs, but the reason for the receiver mods is unclear - maybe a
modification published in a magazine or on the internet ? I've changed the IF
amp (V103) back to a 6BZ6 but left the RF amp (V2) as an EF183/6EH7.

February 2006 - several faults found. The main fault was one of the 6146 PA valves had developed a control
grid to screen grid short-circuit, which put +360V onto the -100V rail, making a
hot smell and possible other as-yet-undetected damage. It is possible that this
6146 was damaged by a problem with C55 (100pF 1kV wkg) - this crucial capacitor
has +360V on 1 side and -100V on the other - the 1kV rating sounds fine until
you factor in any additional RF voltage, localised heat etc. - any leakage of
C55 is a disaster. I've added a 0.01uF 1kV disc ceramic in series with C55. I don't like the look
of the modified neutralising capacitor and there are one or two disconnected
wires which I'll need to trace and properly insulate. The 6JS6C screen supply was originally connected
to the +165V rail, whereas the 6146s need a higher screen voltage so are now
connected to the +360v rail. All the DC voltages are a bit higher than they
should be, but unfortunately there are no other taps on the mains transformer.
Replacing V102 (12AX7) brought the receiver to life, although the AGC 'hang' time
constant seems too short - there is also the characteristic 'popping' sound on
speech-peaks of loud SSB signals.

Aligning the trap coils is proving difficult,
so there is some extra interference on 40m in the evenings until I can sort this
- I'm having some difficulty working out the various frequencies that the coils
are designed to 'trap'.

Realigning the driver coils and replacing a soft 12BY7A driver valve means
the transmitter is now delivering 120W output on 80,40,20 and 15, and about 70W
on 10m. The 6146A P.A. valves (ex Heathkit SB-401e) glow
slightly blue, so will need replaced in the longer term. I'm going to use this
radio on 80m SSB for further testing.

Purchased for NZ $50 (£19) in June 2005, complete with NCX-A AC PSU and the
XCU-27 100kHz Xtal calibrator unit (which plugs into the rear of the transceiver), the
mobile mount and some spare valves. There are also 2 copies of the handbook and
the original July 17th 1964 invoice from Ad.Auriema, Inc of 85 Broad Street, New
York. The National Radio Co. of Melrose, Massachusetts was famous for the wartime
'HRO' receiver. The first-ever SSB transceiver I saw was an NCX-3 - on the cover of the
Dec.1965 'RSGB Bulletin', under the headline 'DXpedition to Agalega'.

I've only spent a short time so far on this transceiver - it works on receive
when powered up, but there is a low gain on TX problem - power output on transmit is
only 60W. The multi-core cable from the PSU may have some insulation
problems, seeming to have 'aged', but otherwise everything is in surprisingly
good condition for a 41-year old radio. The under-chassis wiring (see photo
below) is a model of neatness
- amazing.

Coincidentally, National featured the same underchassis view (see photo below)
of the NCX-3 in their July 1964 QST advert for the radio :-

Purchased for NZ $50 (£19) in August 2005, in good working condition
complete with original headphones and hand-microphone (Microphone - Hand - no.7)
- this is a World War II military HF radio, mostly used by New Zealand forces in
the Pacific.

This is a very interesting radio - see the webpage http://www.nzart.org.nz/nzart/history/zc1/
for some historical information. It runs on 12V DC and has a built-in aerial
tuning unit.. It covers 2 to 8MHz AM/CW,
with RF power output = 1W on a good day. I have the original handbook which
contains the circuit diagram and the original metal case with lid. On CW, you
can work split and use break-in ! This is one of the stars of my collection of
radios ! My aim is to work New Zealand with this ZC1 MkII on 7MHz CW - a tough
task. I've tried a couple of times to break in to the UK 'Boatanchor' net on 80m AM,
but failed - the operators there don't leave many gaps for unexpected callers,
so I gave up. Eventually I'll call in again with a 100W radio, then switch to the ZC1.

Received as part of a swap deal in July 2005 - value = zero. Hmmm... a
real challenge this one ! Dirty, rusty and unloved - I had to use my
angle-grinder to remove the bolts so that I could get the top and bottom covers
off ! This 1960's SSB transmitter uses no less than 20 valves - the PA is 2 x
6146 and there are 11 controls to adjust if you change band !

The underside is in fairly good condition, so it can possibly be made to work
- if I can find the time and motivation. The photo below of the corroded
aluminium scale from the panel meter gives you an idea of the poor condition of
this transmitter :

I've stopped this corrosion in its tracks using clear varnish and unbelievably
the meter movement still works after I cleaned out all the aluminium oxide, so I
will use it. The drive cord of the 'Eddystone' tuning dial has broken, but
that is repairable. I have not looked at the separate power supply yet but it
looks in better condition than the transmitter. January 2006 - I've decided to leave the renovation of this KW Viceroy until
later so that I can concentrate on the transceivers. This KW Viceroy is
probably the saddest specimen in my collection to date.

November 2006 - Alex GD3UMW (GD6IA) gave me a Yaesu FT-One -
thanks Alex ! The FT-One is a welcome addition to my collection, but has
to be the worst 'high-end' radio of all time - a total turkey in all respects !

June 2007 - I purchased a Yaesu FT-101E

May 2009 - I purchased a Yaesu FT-dx-100 - the original, not
the recent FT-100 !!

This lot will keep me busy ! I'm having trouble sourcing enough high-impedance microphones for these
radios, but my friend Graham GM3JQJ has presented me with a 'Coronation 1953'
microphone which will work with most of these radios - thanks Graham! I've also repaired the Heathkit SB-100 in the photo below for Paul ZL2NS.